1. Field of the Invention
Embodiments relate to a secondary battery.
2. Description of the Related Art
With the rapid development of electronics, communication and computer industries, portable electronic devices are now in widespread use. Rechargeable secondary batteries are mainly used as power sources of portable electronic devices.
Batteries having a pack configuration are now widely used as secondary batteries. A pack type battery includes a bare cell for storing and providing electric energy and a protective circuit module for controlling charge/discharge of the bare cell. The bare cell and the protective circuit are combined into one unit.
Among secondary batteries, lithium secondary batteries have an average operating voltage of 3.7 V. Thus, lithium secondary batteries are not compatible with existing AA and AAA-sized primary batteries, which have an operating voltage ranging from 1.2 V to 1.5 V.